﻿using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;
using System.Text.RegularExpressions;

public partial class UserDefinedFunctions
{

    /// 是否匹配正则表达式
    /// </summary>
    /// <param name="input">输入的字符串</param>
    /// <param name="pattern">正则表达式</param>
    /// <param name="ignoreCase">是否忽略大小写</param>
    /// <returns></returns>
    [Microsoft.SqlServer.Server.SqlFunction]
    public static bool RegexMatch(string input, string pattern, bool ignoreCase)
    {
        bool isMatch = false;
        if (!string.IsNullOrEmpty(input) && !string.IsNullOrEmpty(pattern))
        {
            try
            {
                Match match = null;
                if (ignoreCase)
                    match = Regex.Match(input, pattern, RegexOptions.Multiline | RegexOptions.IgnoreCase | RegexOptions.Compiled);
                else
                    match = Regex.Match(input, pattern, RegexOptions.Multiline | RegexOptions.Compiled);

                if (match.Success)
                    isMatch = true;
            }
            catch { }
        }
        return isMatch;
    }

    /// 获取正则表达式分组中的字符
    /// </summary>
    /// <param name="input">输入的字符串</param>
    /// <param name="pattern">正则表达式</param>
    /// <param name="groupId">分组的位置</param>
    /// <param name="maxReturnLength">返回字符的最大长度</param>
    /// <returns></returns>
    [Microsoft.SqlServer.Server.SqlFunction]
    public static string GetRegexMatchGroups(string input, string pattern, int groupId, int maxReturnLength)
    {
        string strReturn = string.Empty;
        if (!string.IsNullOrEmpty(input) && !string.IsNullOrEmpty(pattern))
        {
            try
            {
                Match match = Regex.Match(input, pattern, RegexOptions.Multiline | RegexOptions.IgnoreCase | RegexOptions.Compiled);
                if (match.Success && (groupId < match.Groups.Count))
                {
                    strReturn = match.Groups[groupId].Value;
                    strReturn = (strReturn.Length <= maxReturnLength) ? strReturn : strReturn.Substring(0, maxReturnLength);
                }
            }
            catch
            {
                return string.Empty;
            }
        }
        return strReturn;
    }
}
